1. Field of Invention
The invention relates generally to the field of oil and gas production. More specifically, the present invention relates to a perforating system. Yet more specifically, the invention concerns aligning perforations based on one or more reservoir characteristics.
2. Description of Prior Art
Perforating systems are used for the purpose, among others, of making hydraulic communication passages, called perforations, in wellbores drilled through earth formations so that predetermined zones of the earth formations can be hydraulically connected to the wellbore. Perforations are needed because wellbores are typically completed by coaxially inserting a pipe or casing into the wellbore. The casing is retained in the wellbore by pumping cement into the annular space between the wellbore and the casing. The cemented casing is provided in the wellbore for the specific purpose of hydraulically isolating from each other the various earth formations penetrated by the wellbore.
Perforating systems typically comprise one or more perforating guns strung together, these strings of guns can sometimes surpass a thousand feet of perforating length. In FIG. 1 an example of a perforating system 4 is shown. For the sake of clarity, the system 4 depicted comprises a single perforating gun 6 instead of a multitude of guns. The gun 6 is shown disposed within a wellbore 1 on a wire line 5. The perforating system 4 as shown also includes a service truck 7 on the surface 9, where in addition to providing a raising and lowering means, the wire line 5 also provides communication and control connectivity between the truck 7 and the perforating gun 6. The wire line 5 is threaded through pulleys 3 supported above the wellbore 1. As is known, perforating systems may also be disposed into a wellbore via tubing, drill pipe, slick line, coiled tubing, to mention a few.
Included with the perforating gun 6 are shaped charges 8 that typically include a housing, a liner, and a quantity of high explosive inserted between the liner and the housing. When the high explosive is detonated, the force of the detonation collapses the liner and ejects it from one end of the charge 8 at very high velocity in a pattern called a “jet” 12. The jet 12 perforates the casing and the cement and creates a perforation 10 that extends into the surrounding formation 2. Generally the wellbore pressure is different from the pressure within the formation 2, thus upon perforation pressure equalization occurs between the formation and the wellbore which in turn produces either flow into the wellbore from the formation, or into the formation from the wellbore.